1. Field of the Invention
The field of this invention is depth adjusting systems for power tools. More particularly the field is depth adjusting systems for screw guns in which part of the system is easily removable from the screw gun to gain access to the spindle and screwdriving bit, and the system retains its depth setting when it is replaced on the screw gun.
2. Description of Related Art
U.S. Pat. Nos. 4,647,260 to O""Hara et al. and 5,341,704 to Klemm disclose depth adjusting systems for screw guns.
The O""Hara et al. patent discloses a two piece depth adjusting system comprising an adjustment collar (26, FIG. 2) and a depth locator (28). The adjustment collar releasably attaches to the nose portion (24) of the screw gun. The depth locator (28) engages the adjustment collar (26) through a screw thread arrangement. When attached to the nose portion (24), the adjustment collar (26) is rotated to adjust the axial position of the depth locator (28). The depth locator (28) is prevented from rotating relative to the nose portion (24) so that when the adjustment collar (26) rotates, the depth locator (28) is in turn driven axially through the screw thread arrangement. Indexing means are also provided between the nose portion (24) and the adjusting collar (26) to retain the adjusting collar (26) in a predetermined angular position relative to the nose portion (24) and thus also retain the depth setting of the depth locator (28). However, when the adjusting collar (26) is removed from the nose portion (24), the indexing means no longer retains the angular position of the adjusting collar (26). When a user removes the adjusting collar (26) and the depth locator (28) to, for example, change the screwdriving bit, the depth setting may be lost and will have to be reset when the adjusting collar (26) and depth locator (28) are replaced on the screw gun.
The Klemm patent discloses a two piece depth adjusting system comprising a sleeve (94, FIG. 7) and a depth locator (76). The sleeve (94) is releasably attached to the gear case of the tool. A groove (40, FIG. 2) on the gear case holds a resilient split retaining ring (42). A flange (98) on the sleeve (94) engages and moves over the retaining ring (42) with an audible snap when sleeve (94) is attached to the gear case. The sleeve (94) may be detached by pulling it axially away from the gear case. In the commercial embodiment of the Klemm patent, the force required to detach the sleeve (94) varies and is sometimes excessive when the flange (98) xe2x80x9changs upxe2x80x9d on the retaining ring (42).
Once attached, the sleeve (94) does not rotate or move axially relative to the tool. The depth locator (76) engages the sleeve (94) through a screw thread arrangement. Rotation of the depth locator (76) by the user causes the depth locator (76) to be driven axially by the screw thread arrangement to adjust the depth setting. An indexing means between the sleeve (94) and the depth locator (76) retains the angular position of the depth locator (76) relative to the sleeve (94) and thus maintains the depth setting. Although the indexing means functions regardless of whether the sleeve (94) is attached to the gear case, in order to adjust the depth locator (76), the user must manually turn the depth locator (76) itself. This can be awkward because the radius of the depth locator (76) is relatively small so that turning the locator (76) is not ergonomically comfortable.
It is an object of the invention to overcome these and other drawbacks found in the prior art depth adjusting systems and to provide additional advantageous features.
In one embodiment, a depth adjusting system for removably attaching to a base of a tool comprises an on/off collar removably attachable to the base so that the on/off collar is not rotatable relative to the base when it is attached thereto, an adjusting collar mounted to the on/off collar and being rotatably but not axially moveable relative to the on/off collar, and a depth locator mounted to the on/off collar and being rotatably and axially moveable relative to the on/off collar such that the depth locator moves axially in response to relative rotation between the depth locator and the on/off collar. The depth setting of the depth adjusting system can be adjusted by rotating the adjusting collar which in turn drives the depth locator to rotate in unison, such rotation causing axial movement of the depth locator.
In another embodiment, a depth adjusting system for a screw gun comprises a spindle extending from the screw gun and adapted to receive a screwdriving bit mounted on one end of the spindle for driving a screw into a workpiece, and a removable depth adjusting assembly removably attached to the screw gun. The removable depth adjusting assembly has a central opening therethrough at least partially surrounding the spindle, the opening defining an axis parallel to the rotational axis of the spindle. The removable depth adjusting assembly comprises an adjusting collar rotatably but not axially moveable relative to the screw gun when the removable depth adjusting assembly is releasably mounted to the screw gun, a depth locator operatively associated with the adjusting collar wherein the depth locator moves axially to adjust a depth setting responsive to rotation of the adjusting collar relative to the screw gun, and an indexing means for releasably retaining the adjusting collar in its selected angular position regardless of whether the removable depth adjusting assembly is attached to the screw gun. The indexing means can be overcome to rotate the adjusting collar by a deliberate torque applied to the adjusting collar by a user.
In another embodiment, a depth adjusting system for a tool comprises a base having receiving means, and a removable depth adjusting assembly removably attached to the base. The removable depth adjusting assembly comprises a depth locator whose axial position relative to the base is adjustable while the removable depth stop is attached to the base, and a first collar connected to the depth locator having at least two tabs projecting therefrom which engage with the receiving means when the removable depth adjusting assembly is attached to the base. The tabs have rounded profiles wherein an axial force applied to the collar can engage and disengage the tabs with the receiving means.
In another embodiment, a method for adjusting the depth setting of a depth adjusting system for a screw gun, the method comprises the steps of: rotating an adjustment collar and prohibiting the axial movement of the adjustment collar, causing a depth locator to rotate in response to the rotation of the adjustment collar, and causing the depth locator to move axially in response to its rotational movement, the axial movement of the depth locator effecting an adjustment of the depth setting.